1. Field
The present disclosure relates generally to imaging systems and, in particular, to zoom functions in imaging systems. Still more particularly, the present disclosure relates to changing fields of view in cameras.
2. Background
Imaging systems often have different fields of view. A field of view is the extent to which an imaging system can generate data about the environment around the imaging system. For example, a wide field of view may be used to obtain an image of an entire city. In some cases, it is desirable to generate images about a portion of the city or an object in the city. When objects are magnified and more detail is obtained about those objects, the field of view is often narrower.
In other words, a focal length change is employed to enlarge the objects and obtain more detail. With this focal length change, the field of view becomes narrower. This focal length change may also be referred to as a zoom function.
This zoom function is performed optically, electronically, or some combination of the two. The electronic method is also referred to as a digital zoom. This type of zoom decreases the apparent field of view of the image. A digital zoom emulates a focal length change. A digital zoom may be accomplished by cropping the image down to an area with the same aspect ratio as the original. Interpolation is often performed. This interpolation may cause a loss of detail in the narrower field of view. In other words, the objects in the portion with the narrower field of view may appear larger but may not have as much detail as desired.
With an optical zoom, a smaller field of view is provided through a lens system. This field of view also provides for increased detail about objects within the narrower field of view. This type of zoom is more desirable than a digital zoom. However, an optical zoom may require hardware changes from the current lens system providing the wider field of view to a lens system that provides the desired magnification of the objects.
When moving from a wider field of view to a narrower field of view, a first housing containing a lens system for the wider field of view is switched out for a second housing containing a lens system with a narrower field of view. In other words, the lens system for the wider field of view may be removed, and the lens system for the narrower field of view may be put in place of the lens system for the wider field of view in an imaging system, such as the body of a camera. Alternatively, a single zoom lens may be employed. With either option, the amount of weight and the size of the camera system may be greater than desired. Further, the power requirements for operating a dual lens system may be greater than desired. Moreover, these options limit an operator to a single, narrowed field of view.
Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above as well as other possible issues.